Following placement of dental implants changes to bone level around the implant take place. Platform switching involves the use of an abutment with a smaller diameter than the diameter of the implant shoulder and is considered by some to lead to reduced peri-implant bone loss. The aim of this trial was to assess the effect of platform switching on marginal bone-level alterations at three years.
Health adult patients with sufficient bone height so that no bone recontouring or augmentation procedures were necessary where extraction of teeth had taken place at least 6 months previously were selected. One of each of the standard or platform-switched implants was placed into each of 25 patients with the position of the implant randomised. The size of platform switching (i.e., the circular step) was 0.35 mm. After 3 months of submerged healing, single-tooth crowns were cemented. Bone loss was assessed on radiographs using 6 measurements; vertical bone loss, mesial and distal; horizontal extent of the vertical bony defect mesial and distal; general horizontal bone loss mesial and distal.
- All 25 patients were seen at 3 years, implant survival rate was 100%.
- mean radiographic peri-implant bone loss was 0.69 ± 0.43 mm (platform switching) and 0.74 ± 0.57 mm (standard platform).
- The mean intra-individual difference was 0.05± 0.58 mm (95% CI: –0.19, 0.29).
- Crestal bone-level alteration depended on time (p < .001) but not on platform type
The authors concluded
The present randomized clinical trial could not confirm the hypothesis of a reduced peri-implant crestal bone loss, when implants had been restored according to the concept of platform switching.
Comment
There have been two previous systematic reviews of platform switching (see Dental Elf -17th July 2012) The first which included 10 studies and 1239 implants suggested that there may be a benefit. The second also suggested that there might be a beneficial effect. The studies that have been included in the reviews have been of short duration and generally small and so the available evidence based is weak and limited. Although this present study is small it is of a longer duration. Some of the example radiographs shown in the article show that the implants have been placed side by side which does raise issues about the ability to compare the outcomes because of the potential effect this may have. Until more higher quality studies of a longer duration have been conducted it is unlikely that we will have a definitive answer to questions about the effectiveness of platform shifting.
Links
Enkling N, Jöhren P, Katsoulis J, Bayer S, Jervøe-Storm PM, Mericske-Stern R, Jepsen S. Influence of Platform Switching on Bone-level Alterations: A Three-year Randomized Clinical Trial. J Dent Res. 2013 Oct 24. [Epub ahead of print] PubMed PMID: 24158333
– See more at: http://www.thedentalelf.net/2012/07/17/evidence-of-small-benefit-in-peri-implant-bone-loss-seen-in-first-5-years-with-platform-switching/#sthash.PiR319K8.dpuf
